Emacs Lisp基础数据类型

Table of Contents

• 1. List Data Types

List Data Types

1. 基本类型有: integer, float, cons, symbol, string, vector, hash-table, subr, byte-code function
2. 字符一般以?开头，如(print ?A) => A

3. Symbol: lisp object的符号表示，用来表示object的名称 (symbol-name ‘foo) => “foo”

   • symbol按照存储方式分为两类，一类属于系统symbol,存储在bucket obarray中；一类属于编程使用symbol，使用make-symbol创建，在obarray中查找不到。

   • 常用函数

     func-nameusagedescsymbol-name(symbol-name ‘foo) => “foo”获取symbol名称，返回字符串名称make-symbol(setq sym (make-symbol “foo”)) => foo (eq sym ‘foo) => nil创建非obarray的symbolintern(setq sym (intern “foo”)) => foo (eq sym ‘foo) => t创建obarray 的symbolintern-soft(setq sym (intern “frazzle”)) => frzzle (intern-soft “frazzle”) => frazzle测试symbol是否存在mapatoms(setq count 0) => 0 (defun count-sym (s) (setq count (1+ count))) => count-sym (mapatoms ‘count-syms) => nil count => 1871 unintern delete a symbol in obarray

   • 变量

     var-namedescobarrayit’s a hash-table, used to stored intern symbol

4. String相关函数

   func-namedescstringp objcheck whether object is string typestring-or-null-p objret t if obj is a string or ‘nil’char-or-string-p objret t if obj is a string or charmake-string cnt charret a string made up of COUNT repetitions of CHARstring &rest charsret a string containing the CHARssubstring string st &opt end(substring “abcdefg” 0 3)=> “abc”substring-no-properties str &opt st endlike substring but discards all text propertiesconcat &rest sequencesret new string containing sequencessplit-string str &opt sep omit-nulls trimsplits STRING into substringsvar: split-string-default-separatorssplit-string default sep

5. Lists

   • Association Lists
     关联链表，如: ‘((a . 1)(b . 2))为key, value的键值对，通过相关函数可以做查询，存取操作。
     ‘(a . 1) 和 ‘(a 1)的区别，’(a . 1)是 a和1组成的，而’(a 1)是a和(1)组成。

     1. 相关函数

        • assoc key alist
          获取第一个匹配key对应的键值对，如:

          (assoc 'a '((a . 1) (b . 2) (a . 3))) => (a . 1)

        • rassoc value alist
          获取第一个匹配value值的键值对，如:

          (rassoc '1 '((a . 1)(b . 2)(c . 1))) => (a . 1)

        • assq key alist
          和assoc相同，唯一区别使用eq函数进行比较，而assoc使用的equal比较。如：

          (setq leaves '(("simple leaves" . oak)("compound leaves" . horsechestnut)))(assq "simple leaves" leaves) => nil(assoc "simple leaves" leaves) => ("simple leaves" . oak)

        • rassq value alist
          同assq对应，使用eq比较函数

        • assoc-default key alist &opt test default

        • copy-alist alist
          拷贝alist, 为取值拷贝，非地址拷贝。如:

          (setcdr (assq 3 copy) '("Martian Vacuum Pine"))(cdr (assq 3 needles-per-cluster)) => ("Pitch Pine")

        • assq-delete-all key alist
          返回删除alist所有匹配key取值的键值对，这个函数会破坏入参alist。
          如:

          (setq alist '((foo 1) (bar 2) (foo 3) (lose 4)))=> ((foo 1) (bar 2) (foo 3) (lose 4))(assq-delete-all 'foo alist)=> ((bar 2) (lose 4))alist=> ((foo 1) (bar 2) (lose 4))

        • rassq-delete-all value alist